The objective of our investigation is to determine the enzymatic mechanism involved in cutaneous catabolism. We are purifying and characterizing the major neutral proteinase of human skin and investigating their role in chemotaxis of polymorphonuclear leukocytes and inflammation in general. We have isolated and purified three distinct proteinases from human skin. The smallest molecular weight proteinase has been purified to homogeneity and its chemical characteristics and amino acid composition have been established. Injection of the purified enzyme into rabbit or mouse skin causes infiltration of polymorphonuclear leukocytes. This infiltration of polymorphs can be inhibited by inhibiting the enzyme with the specific inhibitor diisopropyl fluorophosphate. We have produced a mono-specific antibody to our purified neutral proteinase and we will use it to develop a radioimmunoassay. We also intend to use this antibody to localize this smallest proteinase by immunocytochemical means. This study is beginning to define the role of this enzyme in certain diseases of the skin. BIBLIOGRAPHIC REFERENCES: Levine, N. and Lazarus, G.S. Subcutaneous fat necrosis of the abdominal wall induced by paracentesis in acute pancreatitis. Arch. Dermatol. 112:993, 1976.